If I use caffeine to improve my performance, how much should I use?
Caffeine in moderate doses can boost both physical and cognitive performance. It can help maintain alertness when you are doing long boring activities such as highway driving. It is especially effective for enhancing alertness and mental performance when individuals are sleep deprived. However, if you can, it is better to get the sleep your body needs. The suggested level of intake for enhancing cognitive performance is relatively low—one or two cups of coffee or one or two energy drinks (about 80-200 mg of caffeine). Larger doses can cause side effects (e.g. nervousness, irritability, shakiness, and trouble sleeping). It is very important not to consume large amounts of caffeine before trying to sleep. Blood levels of caffeine peak at about 60 minutes and are maintained for approximately two to three hours. Thus, although each person is different, another dose after four hours may confer additional benefits for activities of long duration or when alertness must be maintained. Remember, more caffeine will not improve performance and may actually degrade it due to various negative side effects at higher doses.